2 Definition(s) from various sources:

A cow and her calf were not to be killed on the same day ( Leviticus 22:28 ; Exodus 23:19 ; Deuteronomy 22:6 Deuteronomy 22:7 ). The reason for this enactment is not given. A state of great poverty is described in the words of Isaiah 7:21-25 , where, instead of possessing great resources, a man shall depend for the subsistence of himself and his family on what a single cow and two sheep could yield.